Shotgun barrels often include a choke tube at the distal (i.e., shot-expelling) end. The typical shotgun choke tube is inserted into the barrel to constrict the shotgun's shot charge as the shot charge leaves the muzzle, thereby modifying the spread of the shot charge on its way to a target. For example, a choke tube with more constriction provides for a denser shot pattern at longer range, and a less constrictive choke tube would provide for a less dense shot pattern. Typical shotgun coke tubes screw into the muzzle of the barrel and enable multiple constrictions to be used on the same barrel by changing one choke tube for another.